Galactic¶
-
class
astropy.coordinates.builtin_frames.
Galactic
(*args, copy=True, representation_type=None, differential_type=None, **kwargs)[source]¶ Bases:
astropy.coordinates.BaseCoordinateFrame
A coordinate or frame in the Galactic coordinate system.
This frame is used in a variety of Galactic contexts because it has as its x-y plane the plane of the Milky Way. The positive x direction (i.e., the l=0, b=0 direction) points to the center of the Milky Way and the z-axis points toward the North Galactic Pole (following the IAU’s 1958 definition [1]). However, unlike the
Galactocentric
frame, the origin of this frame in 3D space is the solar system barycenter, not the center of the Milky Way.- Parameters
- data
BaseRepresentation
subclass instance A representation object or
None
to have no data (or use the coordinate component arguments, see below).- l
Angle
, optional, must be keyword The Galactic longitude for this object (
b
must also be given andrepresentation
must be None).- b
Angle
, optional, must be keyword The Galactic latitude for this object (
l
must also be given andrepresentation
must be None).- distance
Quantity
, optional, must be keyword The Distance for this object along the line-of-sight.
- pm_l_cosb
Quantity
, optional, must be keyword The proper motion in Galactic longitude (including the
cos(b)
term) for this object (pm_b
must also be given).- pm_b
Quantity
, optional, must be keyword The proper motion in Galactic latitude for this object (
pm_l_cosb
must also be given).- radial_velocity
Quantity
, optional, must be keyword The radial velocity of this object.
- representation_type
BaseRepresentation
subclass, str, optional A representation class or string name of a representation class. This sets the expected input representation class, thereby changing the expected keyword arguments for the data passed in. For example, passing
representation_type='cartesian'
will make the classes expect position data with cartesian names, i.e.x, y, z
in most cases unless overriden viaframe_specific_representation_info
. To see this frame’s names, check out<this frame>().representation_info
.- differential_type
BaseDifferential
subclass, str, dict, optional A differential class or dictionary of differential classes (currently only a velocity differential with key ‘s’ is supported). This sets the expected input differential class, thereby changing the expected keyword arguments of the data passed in. For example, passing
differential_type='cartesian'
will make the classes expect velocity data with the argument namesv_x, v_y, v_z
unless overriden viaframe_specific_representation_info
. To see this frame’s names, check out<this frame>().representation_info
.- copybool, optional
If
True
(default), make copies of the input coordinate arrays. Can only be passed in as a keyword argument.
- data
Notes
- 1
Blaauw, A.; Gum, C. S.; Pawsey, J. L.; Westerhout, G. (1960), “The new I.A.U. system of galactic coordinates (1958 revision),” MNRAS, Vol 121, pp.123.
Attributes Summary
Attributes Documentation
-
default_differential
¶
-
default_representation
¶
-
frame_specific_representation_info
¶
-
name
= 'galactic'¶